Homeotic Genes

Maternal genes

-Established in unfertilized egg -Specify polarity- anterior-posterior and dorsal-ventral axis of the egg -Regulates expression of all proceeding genes - Encode regulators of transcription and translation

segmentation genes

-Genes that determine the number and polarity of body segments. -The genes of the embryo that direct the actual formation of segments after the embryo's axes are defined.

what doe Hox genes do?

-are transcriptional regulators -can promote or repress gene expression -many transcriptional regulators regulate own genes but also genes in other proteins

Homeotic genes (Hox genes)

-direct formation of particular structures at specific locations (determine where organs/ appendages go) -Expressed in embryo -control development in same order in very different animals -trigger development of structures appropriate to each type of segment -use homeodomain to bind to DNA -expression refined by protein products of gap genes, pair rule genes and interaction with other Hox proteins

Gap genes

-responsible for large multi segment regions -organize cells into groups of segments along anterior-posterior axis -Activated through interactions between protein products of maternal effector genes and each other -mutations result in gaps in embryos segmentation pattern

Pair Rule Genes

-specify division of embryos broad gap domains into segments -divide embryo into units of two segments each -turn on by interaction between gap genes

segment polarity genes

-specify polarities of developing segments -turned on by interaction between pair rule genes -protein products define polarity within each segment of development

Homeotic Genes

Any of the master regulatory genes that control placement and spatial organization of body parts in animals, plants, and fungi by controlling the developmental fate of groups of cells. -act in different regions of the body ensuring each segment takes on correct identity

transcription factors

Collection of proteins that mediate the binding of RNA polymerase and the initiation of transcription.

List the genes in early development cascade

Maternal, Segmentation (gap genes, pair rule genes, segment polarity genes), hox genes

Homeotic gene transcription factors

contain DNA binding protein region called homeodomain encoded by a segment of DNA called homeobox

in animals what is responsible for orderly organization of body parts during development?

master regulatory genes expressed in different regions during development

what are homeotic genes

master regulatory genes that encode transcription factors expressed in specific regions of the body in development. the TF's change expression of target genes to enact genetic program thats right for that segment

Hox genes

series of genes that controls the organs and tissues that develop in various parts of an embryo

what do most homeotic genes encode for

transcription factor proteins that contain region called homeodomain (Hox) Genes

Master regulatory genes

usually transcription factors that control several other genes. These genes turn on the right genetic program for each section of the body